Middle Pleistocene sedimentation and palaeogeography of the Dzierżoniów basin, Sudetic Foreland, Southwestern Poland

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Annales Societatis Geologorum Poloniae (1996), vol. 66: 35 - 58.

MIDDLE PLEISTOCENE SEDIMENTATION

AND PALAEOGEOGRAPHY OF THE DZIERŻONIÓW BASIN, SUDETIC FORELAND, SOUTHWESTERN POLAND

Dariusz KRZYSZKOWSKI1 & Marek IBEK2

d epartm ent o f Geography, WSP Słupsk (correspondence: P.O. Box 202, 53-350 Wrocław, Poland) Geographical Institute, University o f Wrocław, pi. Uniwersytecki 50-137 Wrocław, Poland Krzyszkowski, D. & Ibek, M., 1996. Middle Pleistocene sedimentation and palaeogeography o f the Dzierżoniów Basin, Sudetic Foreland, Southwestern Poland. Ann. Soc. Geol. Polon., 66: 35-58.

Abstract. The Dzierżoniów Basin contains deposits of three glacial stages: older Elsterian, younger Elsterian and older Saalian (Odranian). The first and the last are represented by tills and thin, discontinuous proglacial (transgressive) deposits. Younger Elsterian represents both transgressive glaciofluvial/glaciolacustrine deposits and a till, as well as deglaciation suite. The latter is represented by extensive glaciolacustrine suite, formed in the ice-contact lake, and series o f glaciofluvial deposits. Glacial palaeotransport was from northwest during both Elsterian stadials. During Odranian, two ice lobes occurred, one flowing from north and the second one from northeast. Holsteinian fluvial series occur directly on younger Elsterian deglaciation suites. They represent gravelly or sandy-gravelly sequences deposited by braided rivers. Holsteinian age is inferred from geological position. No pollen data are available. Elsterian and Holsteinian deposits have been tectonically shifted and slighty deformed. The amplitude of tectonic movements is ca 30 - 40 m. Age o f the tectonic movements is, most probably, post-Odranian. Younger Saalian (Wartanian) and Upper Pleistocene sequences are represented mainly by fluvial deposits (valleys) and loess or slope deposits (uplands). Deep valleys were formed during the OdranianAVartanian interstadial, possibly because of increased uplift and regional tectonic movements.

Abstrakt. Kotlina Dierżoniowska zawiera osady trzech zlodowaceń: starszego stadialu zlodowacenia Elsterian, młodszego stadialu tego zlodowacenia i starszego stadialu zlodowacenia Saalian (Odranian). Najstarsze i naj

młodsze osady glacjalne reprezentowane są przez gliny i cienkie, nieciągłe pokrywy transgresywnych osadów glacifluwialnych. Osady młodszego stadiału zlodowacenia Elsterian zawierają osady zarówno z transgresji, w tym gliny, jak i z recesji lądolodu. Osady recesyjne reprezentowane są głównie przez osady zastoiskowe, formowane w proglacjalnym zbiorniku typu ice-contact. Transport glacjalny w czasie obu stadiałów zlodowacenia Elsterian byl z północnego-zachodu. W czasie zlodowacenia Odranian Kotlina Dzierżoniowska była pod wpływem dwóch lobów lodowcowych, jednego transgredującego z północnego wschodu a drugiego z północy. Osady rzeczne z interglacjału mazowieckiego (Holsteinian) leżą bezpośrednio nad osadami recesyjnymi zlodowacenia Elsterian.

Są one reprezentowane przez żwiry i piaski ze żwirami deponowane w warunkach rzeki roztokowej. Wiek tych osadów został określony na podstawie pozycji geologicznej; brak jest danych paleobotanicznych na potwierdzenie tej hipotezy. Osady zlodowacenia Elsterian i interglacjalne osady rzeczne ulegały ruchom tektonicznym. Ich amplituda dochodzi do 30 - 40 m. Wiek ruchów tektonicznych został określony w przybliżeniu na okres po ostatniej transgresji lądolodu (post-Odranian). Osady stadialu Warty i górnego plejstocenu reprezentowane są w Kotlinie Dzierżoniowskiej przez serie rzeczne (doliny) oraz lessy i osady stokowe (wysoczyzny). Głębokie rozcięcia dolinne powstały prawdopodobnie po ostatniej transgresji lądolodu (interstadial OdranianAVartanian), częściowo jako odpowiedź na wzmożone, glaciizostatyczne ruchy podnoszące lub bardziej regionalne ruchy tektoniczne.

Key words: Pleistocene stratigraphy, glacial and fluvial deposits, neotectonics, Sudetic Foreland, Southwestern Poland

Manuscript received 8 December 1995, accepted 25 April 1996

INTRODUCTION

T he p ap e r presents sedim entological and structural data all located w ithin the D zierżoniów B asin, S udetic Foreland from three outcrops: D obrocin, U ciechów and G rodziszcze, (Fig. 1). These data are suplem ented by archival borings o f

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36

D. KRZYSZKOWSKI & M. IBEK

this region. O ur d ata and interpretation differ from th at o f the form er w orks on Q uaternary o f this region (B arsch &

Finckh, 1924; D athe & Finckh, 1924; P em arow ski, 1963;

Szponar, 1974, 1986; W alczak-A ugustyniak, 1977; Szala- m acha & W alczak-A ugustyniak, 1976; W alczak-A ugusty

niak & Szałam acha, 1978) and lead us to present a new m odel o f the M iddle P leistocene sedim entation in the D zier

żoniów Basin. A prelim in ary m odel w as form erly presented by authors in Ibek (1991) and K rzyszkow ski (1993).

M o st o f p resented data com e from eastern part o f the D zierżoniów Basin, w ith tw o large outcrops, D obrocin and U ciechów , and m any archival borings, w hereas w estern part o f th e basin has alm o st no borings and lim ited nu m b er o f good outcrops w ith glacial deposits (K rzyszkow ski, 1993) (Fig. 1). In spite o f such unequal docum entation, it seem s that th e m odel presents correctly sedim entation history on all sides o f the basin.

M ethods, including the petrological investigations, have been described sep arately in C zerw onka & K rzyszkow ski

(1992) and B adura et al. (1992).

GEOMORPHOLOGY AND GENERAL GEOLOGY

The D zierżoniów B asin is an interm ontane basin bo r

dered from all sides by high m ountain ridges o r at least hills (Fig. 1). Its southw estern boundary is fo rm ed by a 400 m high scarp o f the Sudetic M arginal F ault (O bere & D yjor, 1969), w hich separates the S ow ie M ts (1015 m a.s.l.), a part o f S udeten, from the Sudetic F oreland (Fig. 2B ). T he n o rth ern and southern boundaries (K ielczyn H ills, 462 m a.s.l.;

B ielaw a Hills, 455 m a.s.l.) are also distinct, w ith tectonic scarps up to 50 - 100 m. T he eastern boundary at the K rzy

żow e H ills (407 m a.s.l.), a p art o f N iem cz a H ills, although n ot form ing one line, is also quite distinct and form s a 50 - 75 m high scarp (Fig.2A ). N orthw estern and northeastern boundaries o f the D zierżoniów B asin are m uch less distinct

contour lines

A ,

l 2 5 0 - 300ma.s.l.

geological c ro s s se ctio n s

(Fig. 17) ^

i a r e a s below

J 250 m a s l

morphological c ro s s sections ( Fig. 3 )

main riv e rs » location of the a rc h iv a l borin gs

□ q u a rrie s investigated

Fig. 1. The Dzierżoniów Basin at the Sudetic Foreland and location o f sites investigated

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MIDDLE PLEISTOCENE OF DZIERŻONIÓW BASIN

37

Sow;e M ts.

Słęża Massif Niemczo h ills ;

Dzierżoniów BGsin!

Fig. 2. General overview for the Dzierżoniów Basin: A. from Sowie Mountains to NE, on the left side is visible the “flat region” with alluvial veneers (northwest on the left); B. from Dobrocin quarry to the west, at the foreground hilly landscape between Dobrocin and Uciechów (southwest on the left); in both views: D - Dobrocin quarry. U - Uciechów quarry, G - Grodziszcze quarry

and are indicated only by sm all and isolated hills w ith relative heigth up to 20 - 30 m. T hese are: B ojanice (290 m a.s.l.) and K rzczonów (285 m a.s.l.) H ills in the northw est, and Jaźw ina H ills (279 m a.s.l.) in the northeast. These tw o last hill groups form “gates” o f the D zierżo-niów Basin, opened to o ther regions (Fig. 2A , B). The northw est “gate”

is used recently by m ain river o f the basin, the Pilaw a river (Fig. 1) and both “gates” w ere used extensively by rivers and glaciers during the P leistocene (Pernarow ski, 1963).

The basin interior can be subdivided into three parts. The southw estern part, bordered w ith the Sow ie M ts, represents a gently inclined to northeast (ca 2°) alluvial fan (the U pper

T errace level) . T he northw estern and central parts o f the basin form a flat region at about 240 - 250 m a.s.l., w hereas the eastern part o f the basin is characterized by generally higher (260 - 320 m a.s.l.) and hum m ocky m orphology (Figs. 1 ,3 ).

M orphology o f the D zieżoniów B asin is structurally controlled (O bere, 1972). The basin is located at the north

ern flank o f the Sowie G óry gneiss block (Fig. 4A ) (G ro

cholski, 1967; Ż elaźniew icz, 1987), w ith gneiss outcrops at all its boundaries, except K iełczyn H ills w ith serpentinites (M aciejew ski, 1963, 1968). The southw estern, southern, northern and very probably also eastern boundaries are tec-

m a.s.l.

iOO-,

DO BRO CIN

JAŹWINA

UCIECHÓW

GILÓW

bedrock at the ground s u rfa c e :

x x x x x g neiss v v v v v s e r p e n tin ite

KRZCZONÓW

200 J

t,00

D Ż IE R Ż 0 NIĆW

Fig. 3. Morphological profiles throughout the Dzierżoniów Basin (for location see Fig. I)

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39 N

upper g ra v e ls

lower san d s

< - ^{250 m} -3>

Fig. 4. A simplified map o f Dobrocin quarry with location of sections and sedimentological logs (above) and cross section throughout quarries near Dobrocin with correlation of lithostratigraphic units (below)

tonic and follow fault zones in the bedrock. The D zierżo

niów B asin is com posed o f tw o sub-basins. The w estern one is a part o f the R oztoka-M okrzeszów G raben (D yjor & Ku- szell, 1977; G rocholski, 1977) and form 2 - 3 km w ide gra

ben zone, paraleli to the scarp o f the Sudetic M arginal Fault (Fig. 4A ). T hickness o f the C ainozoic deposits reaches here up to 200 m (B ossow ski, 1975). The eastern basin is located on th e tilted gneiss block, w here gneiss is outcroped only at th e graben boundary (Fig. 4A ). T hickness o f the C ainozoic deposits reaches here only up to 40 - 60 m.

S urficial geology w ell correlates w ith m orphological zones. T he B ojanice and K rzczonów H ills are form ed m ainly o f glacial deposits (m oraine plateau) w ith extensive outcrops o f the L ow er and M iddle P leistocene fluvial depos

its (K rzyszkow ski, 1993) and som e gneiss hills. The south

w estern part o f the basin as w ell as the northw estern part o f the flat region are form ed o f post-glacial (post-O dranian) alluvial veneers, w ith som e, isolated patches o f glacial de

posits. The northeastern p art o f he flat region is form ed o f glacial deposits (tills), w ith extensive outcrops o f Pleisto

cene (glaciolacustrine) and/or N eogene clays and silts. The eastern, hum m ocky part o f th e basin, including the Jaźw ina Hills, is form ed m ainly o f glaciofluvial sands and gravels

w ith som e glaciolacustrine deposits and tills, as w ell as som e gneiss hills (Fig. 4B).

From the above it follow s th a t th e bedrock structure controls the basin boundaries, but surficial deposits have only little connections w ith the bedrock, e.g. the R oztoka- M okrzeszów G raben is not clearly visible in local m orphol

ogy. Thus, recent landscape and surficial deposits depend, in m ajority, on sedim entation and erosion rates during the Q uaternary.

DESCRIPTION AND INTERPRETATION OF DEPOSITS

D O B R O C IN

D obrocin quarry is located 1.5 km north o f village D o

brocin, at the top o f the highest hill in this region (322.4 m a.s.l.). The quarry contains three outcrops (Fig. 5). T he old one, num bered 3, is poorly preserved w ith only 1 - 2 m o f non-calcareous gravels near the ground surface. T he new outcrop, num bered 2, contains som e sm all, up to 5 - 8 m high sections o f m edium to fine grained, cross (St, Sr) and

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D OBR OC IN

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NE DOBROCIN E

SW

41

horizontally (Sh) bedded sands. Palaeoflow directions o b tained from St structures are 122 - 302° here. In turn, the m ain outcrop, num bered 1, contains several sections, o f total lenght up to 500 m, in tw o levels. Each level contains sections from 5 to 10 m high (Fig. 6). Total thickness o f the exposed sequence is over 20 m. D etailed sedim entological and structural data, w hich are presented below , com e only from D obrocin 1.

Lithostratigraphy

Five sections, A, C, E, G and K (Fig. 5) have been described in detail; the others w ere not w ell exposed during the investigation period (1989-1992). L ithologically, the se

quence m ay be subdivided into four units, w hich occur in

superposition: low er gravels, low er sands, u pper gravels and u pper sands and silts. Stratigraphically, they m ay be grouped into tw o series: the L ow er M em ber (low er gravels and sands) and the U pper M em ber (upper gravels and upper sands and silts). The m ain difference betw een them is lack o f calcium carbonate in the U pper M em ber. H ow ever, there is neither distinct erosion boundary no r a rapid change in lithofacial characteristics betw een tw o m em bers defined.

H ence, deposits o f D obrocin 1 are interpreted as strati

graphically uniform sequence and n am ed the D obrocin F or

mation. The U pper M em ber is exposed at sections C, D and F, w here both as w hereas series, together w ith the boundary betw een the calcareous and non-calcareous deposits, are exposed at section E (Figs. 6 - 10), and sections G, H and K

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Fig. 7.Sedimentologicallogsofdepositsat Dobrocin1.Locationatfig.5.Facies codeafter Miall(1977, 1978)

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43

Fig. 8. Sediments of the Upper Member at section Dobrocin 1C. A. general overview for the section, the scarp is about 10 m high; west on the left; B. imbricated gravels o f the Gm facies of the upper gravels; C. silt/fine sand suite and cross-bedded sands o f the upper sand and silt unit; D. detailed view of the silt/fine sand sequence; E. the topmost sequence with cross bedded sands interbedded with fine-grained layers (arrows)

contain o nly the L ow er M em ber. Section A contains cal

careous silts and fine sands, w hich cannot be clearly corre

lated w ith the other series due to isolated position o f section.

Section B w as com pletely covered by slum ps (Fig. 5). A correlation w ith the low er sands o f the Low er M em ber is possible (Fig. 7).

T he sedim ents are gently inclined to the S, SW and W at sections C, E and G and to N and E at section A (Fig. 11), b eing m o st probably a part o f the synclinal form with the axis betw een sections C and A (Fig. 5). T he sequence is

crossed by a set o f norm al faults, w hich have no preferable orientation and very often form ing the conjugate system s (Fig. 11).

Correlation o f series from different sections is presented at the cross-section in Fig. 5, w hich is supplem ented by additional data from outcrops 2 an d 3. M oreover, a 6 m thick series o f fine sands has been reported in th e w ater basin betw een sections A and K (personal com m unication from the ow ner o f the quarry).

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44

Fig. 9. S ed im en ts o f the section D obrocin IE. A. G eneral o v erview w ith boundary betw een L o w er and U p p er M em b ers; B. L ow er g rav els w ith visible cro ss-b e d d in g and norm al faulting; C . low er gravels and low er sands, note very d istin c t cro ss b e d d in g and gradual tran sitio n s betw een litliological un its (the section is 10 m high; n o rth east o n the left)

Sedimentary petrology

The tw ofold division o f sedim ents at D obrocin 1 is confirm ed by petrological data. The L ow er M em ber co n tains about 40% o f th e northern rocks, including 16 - 20% o f the B altic lim estones (Fig. 12) and up to 60% o f local rocks, m ainly m ilk quartz ( 1 8 - 2 3 % ) , Sow ie G óry gneiss ( 1 4 - 16%), quartzites (6 - 8% ), porphyres (3 - 5%) and serpentinites (1 - 4% ). T he U pper M em ber, in turn, has only 20 - 25% o f northern com ponent, and only the resistant rocks (m ainly the S candinavian crystalline rocks, M esozoic sand

stone, flint) and no lim estones. Local com ponent o f the U pper M em ber is ch aracterized by large increase o f m ilk quartz ( 1 9 - 3 1 % ) and serpentinites (3 - 10%), as w ell as abundant Sowie G óry gneiss ( 1 1 - 1 9 % ) , quartzites ( 5 - 11%) and porphyres (3 - 8%).

Local rocks show different source areas. The Sow ie G óry gneiss is o utcroped around the D zierżoniów Basin.

This gneiss, together w ith m ilk quartz, quartzite and po r

phyre represent to g eth er a typical rock assem blage found in deposits o f the R iver B ystrzyca (K rzyszkow ski, 1993). The latter is present at th e northw estern boundary o f D zierżo

niów B asin (B ojanice and K rzczonów Hills, Fig. 4B). Ser

pentinites m ay com e from the K iełczyn Hills (N or N E source) or from sm all outcrops o f serpentinites in the east o f the D zierżoniów B asin (Fig. 4A). A n occurrence o f tw o

local gravel assem blages in one fluvial series but indicating different source areas, one in the northw est (porphyre, m ilk quartz, quartzite) and second in the north, n ortheast or east (serpentinite) m ay be explained only by form er glacial m ix

ing. This is quite satisfactory explanation for th e L ow er M em ber, w ith 40% o f northern com ponent suggesting a glaciofluvial origin o f deposits, but it is n o t enough for the U pper M em ber. L acking o f lim estones suggests rather flu

vial origin o f the series.

H eavy m inerals (Fig. 12) also d ifferentiate sedim ents into tw o m em bers. The L ow er M em ber is garnet-predom i

nated (27 - 61% ), w ith am phibole (9 - 26% ) and epidote (6 - 13%). The other m inerals are infrequent, from 2% to 8% . The U pper M em ber is bipartite. The low erm ost part o f the U pper M em ber has alm ost th e sam e m ineral assem blage as the L ow er M em ber, i.e. garnet (40 - 54% ) and am phibole (6 - 27% ) (Fig. 12). The upper part, w hich represents a m ajo r

ity o f the U pper M em ber, is am phibole p redom inated (48 - 88% ). O ther m inerals are in average betw een 2% to 8%.

Sum m arizing, both m em bers have sim ilar m inerals, but they differ clearly from each other in m ineral assem blages. The low er one contains in average gam et (47% ), am phibole (14% ) and epidote (10% ), and can be interpreted as the glacially derived one (glaciofluvial). T he upper assem blage contains practically m ore than 50% o f am phibole, w hen the

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Fig. 10. Sediments at section Dobrocin IK (A, B) and Dobrocin IG (C, D) - note distinct cross-bedding and lithological changes in vertical profiles; E. Grodziszcze: varved clays with layers of deformed sands (arrow): F. Grodziszcze: deltaic fine sands with ripple cross-lamination

Fig. 11. Dips of strata (A) and orientation of faults (B) at Dobrocin 1. A, C, G, E - sites with structural measurments. compare with figs 5 and 6. Schmidt stereonet, southern hemisphere

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Fig. 12

Li i+io- stratigraphy

HEAVY MINERALS QUARTZ ROUNDNESS

0,1 - 0,25 mm 0,5 - 1,0 mm

20 LO 60 80 1 0 0 % 20 LO 60 60 1 0 0 %

GRAVEL PETROGRAPHY 1 0 -3 5 mm

20 LO 60 80 1 0 0 %

upper sands Z silts

Cd LU CD z : LU ________

z :

upper

^gravels

z U J

o ^CL

_

^Q_

t— ^ZD

<

z :

cc silts &

o _sands

Ll_

c e LU CD

'Z.

LłJ X

z lower

UJ sands

o QL COCL_LU

O

□ ^o

lower gravels

25

o ©

-70

- 67

- 65

C H L O R IT E

C H L O R I T E

northern rocks : I + + +| crystalline

|v „ vt,| flin t Baltic limestones

local rocks : o o milk quartz

porphyre 5 s 5s serpentinite I * , * I quartzite r c T i Sowie Qöry L g I gneiss

schists other rocks

+ +

-4- ++

+ + + + + + + + +

-t- + +

+ + + + +4-

gravel sand fine sand silt

garnet amphibole

| feeee| epidote

trough cross bedding planar bedd ripplemarks planar bedding

staurolite andalusite tourmaline zircon

will] kyQnite

TMIimir 1'111■[111

l i l l 'l l 'r

CH

well rounded grains partially rounded grains angular grains

pyroxene biotite chlorite other minerals L ith o stratig rap h y and p etrological properties o f dep o sits at D obrocin

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D o b ro » I ^UPP« ----

[ Lower Member Uciechów — 7 Û

Cfjple d rift Cross-lamination

à A

K + * + /

i Fm. FI, Fr (sill's)

• Sr (fine sands)

■ St,Sh (sands)

X Gt.Gh (gravels)

* 6m (gravels!

poorly sorted sediments

\ □

\

• - ~ » ^ s m a ll scale cross bedding

C < 5 cm I

moderately to wll sorted sediments

Fig. 13. Grain size characteristics o f sediments at Dobrocin 1.

Note similarities between deposits from different lithostratigraphic units. Lithofacial code after Miall (1977, 1978)

low erm ost p a rt o f the sequence is excluded. A m phibole m ay be interpreted as the very local com ponent, w hich m ay com e from am phibolite outcrops found frequently in the east o f the D zierżoniów B asin (Fig. 4A).

Silts and fine sands o f the section A contain a large quantity o f chlorite in the fin est sedim ents (up to 96% ), but sam ples from sands indicate m ineral assem blage sim ilar to L ow er M em ber (Fig. 12).

R oundness o f quartz grains does not differ m uch in both series described (Fig. 12), except probably an increase o f partially rounded grains at th e top o f U pper M em ber, with sim ultaneous decrease o f w ell refunded grains.

Characteristics and origin o f sediments

L ow er M em ber

T he L ow er M em ber has been described in detail at three sections: E, G and K (Figs. 6, 7).

T he low er gravels are 7 - 10 m thick and form laterally and vertically hom ogeneous layer, w ith only trough cross

bedded gravels (sections E and G ) (Fig. 6; Fig. 7 -logs 5, 6

and 7) or w ith trough cross-bedded gravels and pebble sands. O ccasionally, horizontal bedding occurs (section K) (Fig. 6; Fig. 7 - log 8, Figs. 9, 10). T he trough structures are in average 0.3 - 0.6 m high, w ith som e larger structures up to 1.2 m. The lenghts o f structures m ay reach up to 4 - 5 m.

A verage size o f gravels is betw een -4 <f) - -6 <J), w ith m inor portion o f cobbles -6 (J) - -7 $ in diam eter. M atrix consists o f granules and coarse sand (m edium size varies from -0.5 <j) to -2.5 <]), sorting betw een 1.5 <(> to 2.0 <[>) (Fig. 13). P alaeotrans- port in all sections is from N E to SW or SE to N W (Figs. 7, 14).

T he low er sands are 4-7 m th ick and form less uniform bed. Each section (E, G, K) has different sequence (Fig. 6;

Fig. 7 - logs 5, 6, 7 and 8). Section E contains trough cross-bedded pebble sands (Fig. 9C ) and horizontally bed

ded pebble sand. Section K contains practically only trough cross-bedded sand and pebble sand, w ith occasional trough cross-bedded gravels (Fig. 10C, D). T he last structures are quite sim ilar to those o f low er gravels. Section G contains, in turn, trough cross-bedded sand and pebble sand (Fig.

10A, B) as w ell as horizontally bedded sand or gravels and fine to m edium sand w ith sm all-scale cross bedding and clim bing ripple structures. The size o f troughs (St) is sim ilar to the sam e structures noted in the low er gravels. Single gravels m ay reach up to -5.5 ((> — 6.5 c|) in diam eter. S edi

m ents are m uch better sorted (sorting betw een 1.5 - 2.0 <(), m ean size varies from 0 to 3 <(>) (Fig. 13). Palaeoflow is from N E to SW or SE to N W (Figs. 7, 14).

The boundary betw een low er gravels and low er sands is distinct (Fig. 9A, 10D). Palaeoflow and sedim ent p etrologi

cal features (Fig. 8) are, how ever, sim ilar in both units. It seem s, that the L ow er M em ber represents stratigraphically uniform , fining upw ards unit. The low er gravels represent m ost probably a gravelly outw ash fan (“u pper fan” ) w here cross-beeded structures w ere form ed in deep channels. The low er sands represent m ost probably a b raided outw ash o f the less energetic “m iddle fan” , w here cross and horizon

tally bedded sands represent channels w ith an average dis

charge, and gravelly troughs - the channels from floods. The sequences o f fine to m edium sands w ith ripple structures m ay represent abandoned channels (W illiam s & R ust, 1969;

Sm ith, 1974; Eynon & W alker, 1974; B oothroyd & A shley,

• c s t

+ C im bricahon (+100° )

V = 2 U 2 0 v =2ir

Fig. 14. Palaeoflow characteristics o f the Dobrocin Formation: from Lower Member (A), glaciolacustrine silts and sands at section A (B) and Upper Member (C). Schmidt stereonet, southern hemisphere, n - number of measurments, L - vector amplitude, V - mean azimuth

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48

'Sö

— • L J |/ ) _ r _ *0^'S! t_ ^Ol o ^l/J t -^CT

0 0 0 1 0 1 H]

6u)idiiit3s XBoioq4!\

qjdap Lrt

:k>

'Sö

y 3 9 W 3 w

y 3 m o i

U O I j ü L U JO -J

upojqoQ

Fig. 15. Lithostratigraphyand petrological properties ofdepositsatUciechów

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MIDDLE PLEISTOCENE OF DZIERŻONIOW BASIN

49 GRODZISZCZE 2 4 5 m o.s.1.

m SW NE NW SE

V c 158- c la y

157- s i l t

loess-like deposit 290/30

glaciodeltaic deposits fluvial deposits (The Main Terrace) glaciotectonically deformed 2 m

3,51 3

& ⁽¹⁵⁴³

155

I loessic loam I° ° ° I gravel (Gm)

|V*.'| gravel & sand (Qh)

p B l coarse to medium (Sh,St) sand

153

- 2 -1 1

fine sand with ,<■ >

ripplemarks l3 r|

silt (Fm.Fr) varved clay ( Vc ) deformations

Fig. 16. Characteristics o f glaciolacustrine sediments at Grodziszcze: general position at the section (upper right), sedimentological log and sampling (lower left) and grain size characteristics

1975; G ustavson, 1975; Z ielinski, 1993).

Silts and sands at section A

S ection A contains ca 7 m thick sedim entary sequence w hich differs m uch from o ther sedim ents in the quarry (Fig.

6). 1 is represented by 1 - 1.5 m thick, light-grey, m assive silts (m ean grain size, M z 5.9 § , sorting, 1.8 0) w ith single, 1 - 2 cm thick, dark-brow n lam inae o f the clayey silts at the bottom and up to 6 m th ick sandy-silty unit at the top. The last one contains tw o fining upw ards cycles. The low er one is represented by clim bing ripple sands o f type A at the base (M z 2.8 ()>, a 0.6 <|>), and very fine sand/sandy silt (cohesive deposit) w ith clim bing ripples o f type B and S at the top (M z 3.6 - 6.3 a 1.4 - 2.4 (|)). T he upper cycle is represented by fine sands w ith sm all-scale cross bedding at the base and sandy silts w ith clim bing ripples o f type S, B and A at the top (Fig. 7 - logs 1 and 2).

The above described sedim ents m ay represent a se

quence o f the gently inclined delta, w here sandy deposits represent distributory channels and cohesive deposits in

trachannel areas w ith deposition from suspension (Cohen, 1979; L eckie & M cC ann, 1982; A shley el al., 1985). High content o f calcium carbonate and m ineralogical features suggest that silts and sands at section A correlate w ith the L ow er M em ber (Fig. 5). A ccepting that, they m ay represent a glaciodeltaic sequence. P alaeoflow direction is from N E o r N N E to SW or SSW (Figs. 7,14).

U pper M em ber

T he U pper M em ber is up to 1 0 m thick and it has been

described in detail only in section C (Figs. 6, 8).

The upper gravels are com posed of: ca 2 m th ick hori

zontally bedded pebble sands or gravels (Gh) w ith thin layers o f m assive gravels (G m ) and silts (Fm , FI) or fine sands w ith ripple structures (Sr) at the base; and tw o other sedim entary cycles at the top. T hese sedim entary cycles contain m assive gravels (G m ), trough cross-bedded pebble sand (St) and horizontally bedded p ebble sand or fine gravel (Sh, Gh). The low er cycle is ca 1 m and th e upper one ca 3 m thick (Fig. 7 - logs 3 and 4).

G ravels o f the G m facies are up to -7 - -8 $ in diam eter.

T hey are w ell im bricated (Fig. 8B) and com prise coarse sand/granule m atrix. M ean size o f deposit is betw een -0.5 to -2 (|), sorting 2 - 2.5 <|) (Fig. 13). T rough cross-bedded struc

tures are ca 30 - 50 m high and up to 1 m w ide. Palaeoflow m easured from im brication and cross-bedding is from N E to SW (Fig. 7 - logs 3 and 4; Fig. 14).

The upper sands and silts are com posed o f alternating layers o f horizontally o r trough cross-bedded sands (M z 0 - 1.5 <)>, G 0.6 - 1.2 <)>) (Fig. 8C, E) and fine-grained deposits (Fig. 8D). T he latter contains fine sands w ith sm all-scale cross-bedding (M z 2.5 <|>, a 1.8 (j)) or clim bing ripple struc

tures (A and S types) (M z 2.7 <)), a 1.7 <)>), lam inated fine sand and silt (FI) and m assive silts (Fm ) (M z 4.5 ([>, a 2.5 <|>).

Sandy units are usually thicker than fines and reach up to 1 - 2 m , w hereas th e fine-grained d eposits are usually from 10 to 50 cm thick and exceptionally up to 1.5 m in the log 3 (Figs.7, 8A, C and D). U pper boundaries o f fine-grained deposits are usually erosional. Sandy troughs are m o st often betw een 30 - 80 cm high and 1.0 - 1.5 m w ide; at the top o f

4 — A n n a le s S oe ie tatis...

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STRATIGRAPHICINDEXHORIZONS:

50

C VI

I I

II

_vr*o

13

Fig. 17. Geological cross sections throughoutthe eastern pailofthe DzierżoniówBasin(forlocationsee fig.1). Tr- Tertiary deposits, T1- older Elsteriantill, T2- younger Elsteriantill, T3- the UciechówTill (Odranian, lowerSaalian)

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51

sequence w ith som e larger structures up to 1 m high. Pa- laeoflow m easured in cross-bedded structures is from N E to SW or E to W (Fig. 7 - logs 3 and 4; Fig. 14).

D eposits o f the U pper M em ber represent one sedim en

tary environm ent, m ost probably a braided river, although w ith changing palaeodischarge, w hich is m arked by lithol- ogy: m ainly gravelly at the bottom and sandy at he top.

M assive, im bricated gravels represent the longitudinal bars o f the gravel-bearing braided river (W illiam s & Rust, 1969;

Sm ith, 1974, E ynon & W alker, 1974; M iall, 1977). Trough cross-bedded sands and horizontally bedded sands or grav

els at the top o f m assive units m ay represent channel depos

its. The horizontally or trough cross-bedded sandy deposits from the u pper part o f the sequence represent also channel deposits, but from less energetic conditions. In turn, fine

grained deposits m ay represent abandoned channels and deposition during low w ate r stages. The facies assem blage from the U pper M em ber w ell corresponds w ith the m odel o f m ixed braided river (Saskatchew an R iver facies m odel after M iall, 1977, 1978).

UCIECHÓW

The U ciechów quarry is located about 0.5 km east o f village U ciechów (Fig. 1). A ll sections o f this quarry, except the eastern one, w ere covered by slum ps during the investi

gations. T he eastern section w as also not well preserved (Fig. 15). D eposits have been observed only at the lowest part o f section and at its top. A t the base, there are horizon

tally bedded gravels w ith ca 10 cm thick clay layer. A t the top o f th e section, there are fine sands/sandy silts with clim bing ripple structures or m assive silts and clays which are quite sim ilar to th at o f section A o f D obrocin 1 (Fig. 9);

alternating thin layers o f sands and tills (ca 40 cm ) (flow till sequence?); and ca 2 m thick till horizon. The latter is reddish-brow n, decalcified and com pletely w eathered. Lat

erally, the till transits into boulder lag. T here is 0.5 - 1.0 m o f carbonate-free sand above the till and at the ground surface.

G ravel petrography and heavy m inerals suggest (Fig.

15) that sedim ents at U ciechów m ay correspond w ith the L ow er M em b er o f D obrocin, w ith the low er gravels and glaciodeltaic silts and sands (section A ), respectively. A n additional unit, the till, lies directly above the glaciolacus

trine sequence. G ravel petrography o f the till is very sim ilar to gravels below. This suggests sim ilar source o f m aterial, for both glaciofluvial deposits and the till.

T he till bed o f U ciechów has been nam ed the Uciechów Till, athough it cannot be form alized, yet, due to pausity o f data.

G R O D Z ISZ C Z E

T he G rodziszcze outcrop is located ca 0.5 km w est o f village G rodziszcze. It contains ca 5 - 6 m o f the glacitec- tonically deform ed sedim ents (Fig. 16). Stratigraphically low er sedim ents are represented by fluvial gravels o f the B ystrzyca River, w hich b elong to the M ain T errace se

quence o f possible H olsteinian age (K rzyszkow ski, 1993).

The 2.5 in th ic k glaciolacustrine sequence is observed above

fluvial gravels. The deform ed sedim ents, described above, are covered discordantly by 0.5 m loessic loam w hich lies at the ground surface. In the neighbourhood, the till bed w as docum ented at patches on the ground surface (Fig. 4B ) and covers both fluvial gravels and glacial deposits. Strati

graphically it should be placed betw een loessic loam and glaciolacustrine sequence.

The glaciolacustrine sequence is com plex. It contains four layers o f varved clays, each 10 - 40 cm thick (Fig. 10) w hich are separated from each other by m edium to sm all- scale cross-bedded sands (Sr, St) (Fig. 10F), horizontally bedded sands (Sh) and fine sands/sandy silts w ith clim bing ripple structures (Fr). Sporadically, there are also gravels (G m ) and m assive silts (Fm ). A part o f sandy sedim ents are strongly deform ed (Fig. 10E). V arved clays are represented only by several silty-clayey couplets; the m ost thick layer consists o f 6 couplets. The black clays are 0.5 - 1.0 cm thick and light grey silts nev er exceed 5 cm.

The sequence as a w hole m ay represent a glaciodeltaic environm ent, w here varved clays m a y originated at the low er delta slope in quiet areas betw een distributary chan

nels. T he latter w ere p redom inated by sand deposition (A sley, 1975; A shley et a l., 1985; C ohen, 1979, Leckie &

M cC ann, 1982). The glaciolacustrine/glaciodeltaic sedi

m ents o f G rodziszcze, although not identical w ith those o f D obrocin 1A and U ciechów , represent a sim ilar environ

ment.

ANALYSIS OF BOREHOLE DATA

The borings concentrate in the N E part o f the D zierżo

niów Basin, betw een U ciechów , T uszyn and N ow izna, and near D zierżoniów (Fig. 1). The w estern part o f the basin has inadequate num ber o f borings to present there a cross sec

tion. T he archival boreholes have been used, and h ence only lithological descriptions o f cores w ere available.

The geological cross-sections (Fig. 17) show , th at the elevated area betw een D zierżoniów , D obrocin, U ciechów and W łóki represents the horst, th e D obrocin-W łóki horst, w ith the gneiss bedrock at least 270 - 280 m a.s.l. near D obrocin quarry and steeply dipping to the north and the w est. Som e borings, w hich com e dow n to the bedrock, indicate lack o f N eogene deposits at the horst, w ith the Pleistocene till or sand directly on gneiss. T hese new data allow to change the interpretation o f lateral extent and gen

erally dim inish the N eogene deposits in the D zierżoniów Basin in com parison w ith older m aps (Fig. 4A ) (com pare w ith B ossow ski et al., 1981; G rocholski e t al., 1981).

The northeastern part o f the D zierżoniów B asin con

tains 30 - 50 m o f Pleistocene deposits. T hese are rep re

sented by tills and other diam ictons, silts, varved clays, sands and gravels; occasionally also w ith loess at the ground surface (Fig. 17). The N eogene clays have been described in borings at 210 - 220 m a.s.l., i.e. 30 - 40 m below ground surface. M ost often they are superim posed by tills; m ore rarely by sands and gravels. T he latter are also d escribed as glacial deposit. I f interpretation o f deposits o f archival bo r

ings is correct, w e m ust reduce m uch the thickness o f N eo -

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52

Makowice Grodziszcze Tuszyn- Borowica-Albinöw Uciechów Dobrocin

’ W e ich selian

B y s tr z y c a f e

& P iła w a < Eem ian i R ,v e rs IW a rta n ia n

H T - M a in Terrace UT - Upper Terrace M T - M iddle Te rra ce I T - Low er Terrace

g laciofluvial deposits glaciolacustrine

deposit’s subaqueous diamic tons

0 o

© O

0 o O 0

--- C O dranian

H o ls te in ia n ( P iła w a R iv e r)

E ls te r ia n 2

(d é g la c ia tio n s u ite ) O

O o o

° 0 °

?

? E ls te r ia n 2

X X

X X X X X

X X X

X

X X

E S I Upper P leistocene j j j f lu v ia l deposits

loess or loessic loam

? s tr a tig r a p h ie u n its w ith am biguous docum entation

Fig. 18. S tratig rap h y o f the P leisto c en e deposits in the D z ierżo n ió w B asin

gene series and its vertical extent in the basin. O n older m aps (B arsch & F inckh, 1924; D athe & Finckh, 1924; Sza- ła m a c h a & W alczak-A ugustyniak, 1976; W alczak-A ugusty- niak & S załam acha, 1978; G rocholski et al., 1981), the N eogene deposits are m arked on th e ground surface, up to 250 - 270 m a.s.l.. In the light o f data from borings, it seem s th at clays on the gro u n d surface are represented rather by the P leistocene glaciolacustrine deposits than N eogene se

ries (Figs. 4B, 17). N o n e o f borings in the northeast part o f the basin has rea ch ed the base o f T ertiary deposits; thus we suppose th at they are about 30-50 m thick (Fig. 17).

The southw estern p art o f the D zierżoniów B asin (Roz- toka-M okrzeszów G raben) contains up to 30 m o f the P leis

tocene deposits, but very often, in the valley o f P iław a ri ver, they are reduced to 10 - 15 m. T he top o f T ertiary clays are at 240 - 250 m a.s.l. herein. Total thickness o f the N eogene series is from 50 m near D zierżoniów up to 200 m near L utom ia (B ossow ski, 1975).

T he P leistocene sequence o f the D zierżoniów B asin is com posed o f four series: the low er till and sand/gravel; the m iddle till and silt/sand/gravel; the upper series o f alternat

ing silt, varved clay, sand, diam ictons (till) and occasionally gravels, w hich are all strongly laterally variable; and the u pperm ost till.

O nly in a few borings, sandy-gravelly series occurs below the low er till. In turn, gravels and sands are present quite com m only betw een the low er and m iddle tills as w ell

as varved clays and silts (Fig. 17). T he low er till is from a few m etres to 15 m thick, and lies on gneiss o r T ertiary deposits, or occasionally on P leistocene gravels. T he m iddle till is from 2 to 10 m thick. T he upper boundaries o f these tills are, m ost probably, erosional (Fig. 17). T ill beds lie usually at 220 - 240 m , except the D obrocin-W łóki horst area, w here these tills w ere found at least at 250 - 260 m a.s.l.. The upper till is usually thinner, from 1 to 5 m, and occurs usually at ground surface at different altitudes, from 250 to 320 m a.s.l. (Fig. 17). T he upper till m ay be easily correlated w ith the U ciechów Till from U ciechów quarry and it represents the youngest glacial advance in the region.

The series, lying betw een th e m iddle and u pper tills, is very com plex. S trong lateral lithological variability, from coarse gravels to varved clays in neighbouring borings as w ell as the occurrence o f m any diam icton (till) beds w ithin this fine grained series m ake som e problem s w ith in terpretation (Fig.

17). It seem s that this series m ay represent a com plex glaciolacustrine sequence, w here coarse deposits (sands, gravels) m ay represent the u pper delta, fluvial deposits;

sands, silts, clays w ith diam icton (till) and gravel layers m ay represent the proxim al part o f the glacial, ic e-contact lake;

and fine sands, silts and varved clays m ay rep resen t distal parts o f this lake (R ust & R om anelli, 1975; A shley e t al., 1985). The thickness o f the described series is from 5 m to 25 m. The m axim um thickness o f varved clays or m ixed sequences o f varved clays and diam ictons is 1 0 - 1 5 m,

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53 Elsterian 1 & 2 - ice sheet advances Holsteinian

_o___I River alluvial fan

1 proglacial lakes

glacial palaeotransporf 1 - older E lsterian advance 2 - younger Elsterian advance\

Ząbkowice

Elsterian 2 -deglaciation

B

5 thickness of the glaciolacustrine sequence

Fig. 19. Palaeogeographic interpretation o f four case events (A-D) during the Middle Pleistocene in the Dzierżoniów Basin. Detailed discussion in the text

although thickness o f th e entire glaciolacustrine series is very variable, being 10 - 20 m in the N E part o f the basin and near D zierżoniów and below 10 m (usually 5 m) be

tw een these tw o areas. T he zone o f reduced thickness o f the glaciolacustrine series w ell corresponds with the gneiss horst D obrocin-W łóki. In the instance o f this horst, low er boundary o f th e varved clay/silt series lies higher, from 260 to 300 m a.s.l., than in the subsided areas (220 - 250 m a.s.l.) (Figs. 17, 18).

INTERPRETATION

S T R A T IG R A P H Y

T he stratigraphie interpretation o f th e data presented above is quite difficult, especially because the lithostratigraphic sequence from borings is am biguous. A lso, the cor

relation o f Iithostratigraphic units from borings and quarries is quite difficult, as they have no good m arker layers. The

m odel presented below takes into ac co u n t the follow ing data (see also Fig. 17, 18):

1. In the D zierżoniów B asin there are three glacial hori

zons, including three tills, w hich presum ably rep resen t three ice-sheet advances: tw o from E lsterian and one from older S aalian glaciations. A lthough w e noticed m ore till layers in th e borings, all the others than these three w e interpreted as glaciolacustrine diam ictons (subaqueous tills). F rom re

gional studies (B adura et al., 1992; C zerw onka & K rzyszk

owski, 1992; K rzyszkow ski & C zech 1995), w e stated that only three glacial horizons are w ell docum ented in SW Poland. The occurrence o f any m ore glacial advances is unlikely. This view contradicts w ith the interpretation o f W alczak-A ugustyniak (1977).

2. The L ow er and U pper M em bers o f D obrocin quarry have no erosional boundary, and from sedim entological de

scription it seem s that these tw o series w ere d eposited con

tinuously, although the low er one represents a glaciofluvial outw ash and/or glaciodeltaic suites, an d th e upper one flu

vial environm ent (braided river).

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54

/

/ glaciofluvial & glaciodeltaic V transport during the Elsterian rj;—^-| preserved Holsteinian

fluvial deposits 5 -7 possible Holsteinian

^ palaeovalleys

amphibolites 1 possible sources basalt n e c k s ] of the ««»Phibole i glacial transport during the

^ Odranian stage

F ig . 2 0. P alaeo flo w s d o cu m en ted in fluvial and glacial sedim ents o f D obrocin, U ciechów and G ro d ziszcze qu arries. P o ssib le H olste

inian liv e r co u rses are discu ssed in detail in the text. A ltitude: w hite - b elo w 250 m a.s.l., d o t t e d - 2 5 0 -3 0 0 m a.s.l., l in e d - a b o v e 300 m a.s.l

3. T he glaciodeltaic silts o f D obrocin and U ciechów represent the sam e stratigraphie unit and they correlate, m ost probably, w ith the upper (glaciolacustrine) series from the borings. This unit is interpreted to represent a déglacia

tion series after d ecay o f the Y ounger Elsterian ice-sheet (m iddle till). The erosional form s at the top o f the m iddle till m ay represent tunnel valleys.

4. The deposits from U ciechów and D obrocin quarries are covered by th e youngest, U ciechów Till (Saalian) (Figs.

4B, 17) and are underlain, m ost probably, by low er and m iddle tills (Elsterian) or at least by the last one (Fig. 17).

5. T he P leistocene stratigraphy o f the w estern part o f the D zierżoniów B asin was discussed ealier by K rzyszk

ow ski (1993). In th e latter zone, the Elsterian glacial depos

its are n o t w ell docum ented and the Saalian one lie on fluvial deposits o f the M ain T errace o f the B ystrzyca River (H olsteinian?).

6. The m ost controversial interpretation is the status o f fluvial deposits at D obrocin (U pper M em ber o f th e D obro

cin F orm ation). T h ey have never been defined before as

fluvial, and w ere usually interpreted as glaciofluvial depos

its (Pem arow ski, 1963; Szponar, 1974, 1986). T h eir p o si

tion betw een the E lsterian sequence (till and deglaciation series) and the Saalian till suggests sim ilar age as the M ain T errace o f the B ystrzyca R iver, i.e. H olsteinian. It m ust be stressed, how ever, that there w as continuous sedim entation o f braided rivers since the b eginning o f ice sheet decay, to the beginning o f the H olsteinian at least.

7. A ll the other interpretations are consequent to these above. The idealized m odel o f the P leistocene stratigraphy o f the D zierżoniów Basin is p resented in Fig. 18.

P A L A E O G E O G R A P H Y

G laciofluvial deposits o f th e D zierżoniów B asin contain m ixed m aterial o f the B ystrzyca R iver alluvium and serpentinites. O nly one logical explanation is th at th e Elsterian ice-sheets advanced from north, crossing both B ystrzyca preglacial (Pliocene) alluvial fans and K iełczyn H ills w ith serpentinites (Figs. 4, 19A). This local ice m o v em en t w ell

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M ID D L E P L E IS T O C E N E O F D Z IE R Ż O N IÓ W B A S IN

55 NW SE

Tr Tertiary m 1111 n Elsterian deposits UH Hill deposits

Odranian till

Holsteinian fluvial deposits

Wartanian /Eemian fluvial deposits lglaciolacustrine

J deposits

I glaciofluvial

I deposits x x

v v

bedrock gneiss serpentinites

Fig. 21. Tw o alternative models o f glaciolacustrine sedimentation during the deglaciation phase o f the younger Elsterian stadial in thf Dzierżoniów Basin. A. - w ith stable basement; B. - with inferred neotectonic m ovem ents (com pare with fig. 19, discussion in the text)

fit w ith th e re g io n a l o n e , w h ic h fo r th e E lste ria n is g e n e ra lly fro m n o rth w e s t on th e S ile sia n L o w la n d (C z e rw o n k a &

K rz y s z k o w s k i, 1992) a n d fro m n o rth w e s t o r n o rth in th e n o rth e rn p a r t o f th e S u d e tic F o re la n d (K rz y sz k o w sk i &

C z e c h , 1995). A n o c c u rre n c e o f th in la y e rs o f v a rv e d c la y s an d silts d ire c tly b e lo w th e m id d le till (F ig s. 17, 18) su g g ests th a t sh o rt-liv in g p ro g la c ia l lak e m a y h a v e b e e n fo rm e d d u rin g th e a d v a n c e o f th e Y o u n g e r E lste ria n ic e -sh e e t (F ig.

19A ).

A p a rtia l d e c a y o f th e Y o u n g e r E lste ria n ic e -sh e e t in th e D z ie rż o n ió w B a sin c re a te d c o n d itio n s a v a ila b le fo r a larg e a n d re la tiv e ly lo n g -liv in g p ro g la c ia l la k e (F ig. 19B ). T h is w a s m o s t p ro b a b ly an ic e -c o n ta c t lak e in its N E p art, w h e re fin e -g ra in e d d e p o sits a re in te rb e d d e d w ith g ra v e ls, san d s a n d d ia m ic to n s . O th e r m a rg in a l z o n e s re p re se n te d , m o s t p ro b a b ly , g e n tly in c lin e d d e lta s su p p o rte d b y b ra id e d riv ers, e.g . d e p o s its fro m D o b ro c in a n d U c ie c h ó w q u a rrie s (F ig.

19B ).

T h e s u b s e q u e n t d e c a y o f E lste ria n ic e -sh e e t an d o p e n in g o f “ g a te s ” o f th e D z ie rż o n ió w B a s in in th e N W an d N E c a u s e d d ra in a g e o f th e lak e a n d c o n se q u e n tly th e flu v ial

d e p o sitio n started . In th e w e s te r n m o s t p a rt o f th e b a sin , ar ex te n s iv e a llu v ia l fan o f th e B y s tr z y c a R iv e r h a s b eer fo rm e d (K rz y sz k o w sk i, 1993) (F ig s. 4 B , 19 C ). In th e e a s t

ern p a rt, th e flu v ia l d e p o sits w e re d o c u m e n te d in o n e , is o lated p o sitio n a t D o b ro c in . M e a s u rm e n ts in cro ss-b ed d in g a n d im b ric a tio n su g g e s t p a la e o flo w fro m th e N E . T h e re su lts o f h e a v y m in e ra l a n a ly s e s s u g g e s t p a la e o flo w frorr K rz y ż o w e H ills w ith a m p h ib o lite o u tc ro p s (N E to SE ) G ra v e l p e tro g ra p h y in d ic a te s o n ly th e re d e p o s itio n o f oldei g la c io flu v ia l d e p o sits.

T h e a n a ly s is o f to p o g ra p h ic a n d g e o lo g ic a l m a p s has in d ic a te d p o ss ib le p o sitio n o f th e a n c ie n t riv e r v a lle y as p re s e n te d in F ig. 20. It se e m s, th a t th is riv e r re p re se n te c p re -P ita w a R iv er.

R e c e n tly , P iła w a R iv e r h a s b e e n ru n n in g S E -N W , fron:

P iła w a G ó rn a d ire c tly to D z ie rż o n ió w . D u rin g th e H o ls te in ian , th is riv e r h a d ru n a t first n o rth w a rd s , to G iló w B asin, a n d th a n to N W , to D o b ro c in an d a t th e e n d to S W tc D z ie rż o n ió w (F ig s. 19C , 2 0 ). T h is riv e r c o u rs e h a s nevei e x c e e d e d a ltitu d e 3 20 m a .s.l., a n d is w e ll m a rk e d b y w ide v a lle y s, d rie d up o r w ith sm a ll riv e rs (F ig . 2 0 ), a n d co vered

(22)

56

D. K R Z Y S Z K O W S K I & M. IB E K

la te r b y th e S aalian g la c ia l d ep o sits.

D u rin g th e o ld e r S a a lia n , th e D z ie rż o n ió w B a sin w as ag a in c o v e re d b y an ic e -sh e e t. It a d v a n c e d fro m tw o d ire c tio n s: fro m N (K rz y s z k o w s k i & P ijet, 1993a) o r N W (g la c io te c to n ic d e fo rm a tio n s a t G ro d z is z c z e ) in th e w e ste rn p a rt o f th e b a sin , a n d fro m N E o r N in th e e a ste rn p a rt o f th e b a sin (U c ie c h ó w ) (F ig s. 15, 19D , 2 0). S m all, s h o rt-liv in g p ro g la c ia l lak es m a y h a v e b e e n fo rm e d b e tw e e n th e s e tw o ice lo b e s, w ith th e e x a m p le o f g la c io d e lta ic s e q u e n c e at G ro d z is z c z e (F ig. 19D ).

P o st-g la c ia l (p o s t-O d ra n ia n ) h is to ry o f th e re g io n starts fro m g e n e ra l in c isio n a n d fo rm a tio n o f d eep v a lle y s. A t th is tim e , th e n e w v a lle y o f P iła w a R iv e r w as fo rm e d . L ater, n e w v a lle y s w e re fille d w ith flu v ial d e p o sits o f th e U p p e r T e rra c e (Y o u n g e r S a a lia n ), w h ic h c o v e re d e x te n s iv e ly c e n tra l p a rt o f th e b a sin (F ig . 4 B ). T h e U p p e r P le isto c e n e h is to ry is c h a ra c te riz e d b y an a lte rn a tin g in c isio n a n d a g g ra d a tio n in riv e r v a lle y s (M id d le an d L o w e r T e rra c e s ) an d lo e s s-lik e d e p o sits fo rm a tio n a t th e u p la n d s.

POSSIBLE TECTONIC MOVEM ENTS DURING THE PLEISTOCENE

W h e n in te rp re tin g th e p o s t-E lste ria n p ro g la c ia l lak e w e h a v e ig n o re d so m e d a ta . L o w e r b o u n d a ry o f th e g la c io la c u s trin e se rie s a t th e D o b ro c in -W łó k i h o rs t lies a t 2 7 0 m a.s.l.

(U c ie c h ó w q u a rry ) a n d a t c a 3 00 m a.s.l. (D o b ro c in q u arry ), i.e. c a 4 0 - 70 m h ig h e r th a n lo w e r b o u n d a ry o f g la c io la c u s trin e d e p o s its in b o rin g s a t B o ro w ic a , A lb in ó w and T u sz y n . M o re o v e r, g la c io la c u s trin e d e p o sits are v e ry th in in th e h o rs t z o n e (F ig s. 17, 19B ). T h e re are tw o p o ss ib le in te rp re ta tio n s. T h e first o n e s u s p e c ts a n in a c tiv e h o rst c o v e re d w ith a t le a s t 80 m d e e p w a te r, w ith th e d e lta ic , sh a llo w w a te r d e p o s itio n in th e m o s t e le v a te d zo n e n e a r D o b ro c in an d U c ie c h ó w (F ig . 21 A ). T h e se c o n d in te rp re ta tio n su s p e c ts th e te c to n ic u p lift o f th e D o b ro c in -W łó k i h o rs t a fte r th e E lste ria n .

In th is c ase, g la c io la c u s trin e se d im e n ts w e re d e p o site d o rig in a lly in m u c h lo w e r p o sitio n , an d th e n u p lifte d into d iffe re n t h e ig h ts (F ig . 2 1 B ). T h is m o d e l e x p la in s a d d itio n a lly w h y H o lste in ia n g ra v e ls a re p re s e rv e d o n ly a t D o b ro c in - th e y h a v e re a c h e d w a te rs h e a d p o sitio n a fte r u p lift, w h e re a s in o th er, lo w e r p a rts o f th e b a sin th e y w ere m o v e d o u t b y y o u n g e r riv e rs d u rin g U p p e r P le isto c e n e e ro s io n p h a se s . D e p o sits a t D o b ro c in q u a n y a re d e fo rm e d into w id e -ra d iu s folds w h ic h a re a ss o c ia te d w ith n o rm a l, c o n ju g a te fa u lts (F ig. 11). B o th th e s e fe a tu re s are c h a ra c te ristic fo r la rg e -sc a le g ra v ity te c to n ic s , ra th e r th an fo r g la c io te c - to n ic s o r d e a d -ic e m e ltin g d e fo rm a tio n s. It seem s, th a t th e u p lift o f th e D o b ro c in -W łó k i h o rs t as w ell as all m o u n ta in rid g e s a ro u n d th e D z ie rż o n ió w B a sin m a y be c o n n e c te d w ith th e g la c io -is o s ta tic re b o u n d . T h is m ig h t h a v e h a p p e n e d a fte r th e E lste ria n o r a f te r th e la st g la c ia tio n (o ld e r S a a lia n ).

T h e o ld e r S a a lia n a g e o f te c to n ic u p lift in c e n tra l S u d eten w a s d o c u m e n te d b y K rz y s z k o w s k i & P ije t (1 9 9 3 b ) an d P ije t

& K rz y sz k o w sk i (1 9 9 4 ). H e n c e , d e e p in c isio n a n d fo rm a tio n o f n e w riv e r v a lle y s a fte r d e c a y o f th e o ld e r S a a lia n ic e - s h e e t m ig h t h a v e b e e n in d u c e d d u e to te c to n ic m o v e m e n ts, to o .

DISCUSSION

T w o o p p o site m o d e ls h a v e b e e n c o n c lu d e d fo r d ep o sits o f th e D z ie rż o n ió w B asin b y fo rm e r a u th o rs. P e m a ro w s k i (1 9 6 3 ) in te rp re te d a ll sa n d y a n d g ra v e lly d e p o s its as g la c io flu v ia l series, in fillin g th e b a sin d u rin g c o ld stag es.

T h e h illy la n d sc a p e , in h is o p in io n , is e ro s io n a l a n d p o s t

glacial. S z p o n a r (1 9 7 4 , 1986) in te rp re te d th e d e p o sits also as g la c io flu v ia l, b u t h illy la n d s c a p e w a s in te rp re te d as k a m e s o r k a m e p la te a u , c o n s e q u e n tly b e in g d e p o s ite d d u r

in g th e d e g la c ia tio n . B o th in te rp re ta tio n s a re u n s a tisfa c to ry , m a in ly b e c a u se th e flu v ia l (lo c a l) series h a v e b e e n in te r

p re te d as g la c io flu v ia l series. T h e e ro s io n a l o rig in o f h ills by P e m a ro w s k i (1 9 6 3 ) is a c c e p ta b le , b u t w e s u g g e s t also the P le isto c e n e te c to n ic u p lift fo r th e h ig h e s t h ills n e a r D o b ro c in (D o b ro c in -W łó k i h o rst). In o ld e r w o rk s, sa n d y -g ra v e lly d e p o sits w e re a lw a y s c o n n e c te d w ith th e o ld e r S aalian g la c ia tio n . W e h a v e in te rp re te d th e m as th e E lste ria n d e p o s its, a n d also a p a rt o f th e m as th e H o ls te in ia n flu v ia l series.

B o rin g s o f th e D z ie rż o n ió w B a sin w e re in te rp re te d fo r

m e rly b y W a lc z a k -A u g u s ty n ia k (1 9 7 7 ). S h e fo u n d fo u r g la cial h o riz o n s, in c lu d in g o n e p re -E ls te ria n , a n d th e H o ls te in ian la c u s trin e d e p o sits. W e d is a g re e w ith th is in te rp re ta tion. T h e o c c u rre n c e o f p re -E ls te ria n till is u n lik e ly , ta k in g into a c c o u n t a re g io n a l c o n te x t (B a d u ra e t a i , 1992; C z e r

w o n k a & K rz y sz k o w sk i, 1992; K rz y s z k o w s k i & C zech , 1995). P o lle n d ia g ra m (S z c z y p e k , 1977) fro m “ la c u s trin e ” d e p o sits sh o w s c le a rly m ix e d p o lle n , b o th T e rtia ry a n d Q u a te rn a ry , a n d m u s t re p re s e n t re d e p o s ite d m a te ria l. T h e m ix e d p o lle n a ss e m b la g e s are q u ite c o m m o n in p ro g la c ia l lak es, w h ich w a s a lso d o c u m e n te d in th e S u d e te n a n d S u d e tic F o re la n d (J a w o rs k a 1971, 1973).

CONCLUSIONS

1. T h e D z ie rż o n ió w B a sin c o n ta in s d e p o s its o f th re e g la c ia l stag es: o ld e r E lste ria n , y o u n g e r E lste ria n a n d o ld er S aalian (O d ra n ia n ). T h e first a n d th e la st o n e a re re p re s e n te d b y tills a n d th in , d is c o n tin u o u s p ro g la c ia l (tra n sg re ssiv e ) d e p o sits. T h e y o u n g e r E lste ria n d e p o sits c o n ta in s bo th tra n sg re s siv e g la c io flu v ia l/g la c io la c u s trin e d e p o s its a n d a till as w e ll as d e g la c ia tio n su ite . T h e la s t o n e is re p re s e n te d b y a n d e x te n s iv e g la c io la c u s trin e su ite , fo rm e d in th e ice- c o n ta c t lak e, a n d series o f g la c io flu v ia l d e p o sits.

2. G la c ia l p a la e o tra n s p o rt w a s fro m n o rth w e s t d u rin g b o th E lste ria n sta d ia ls. D u rin g O d ra n ia n , tw o ic e lo b e s h a v e b e e n d o c u m e n te d , o n e flo w in g fro m th e n o rth a n d th e s e c o n d o n e fro m n o rth east.

3. H o lste in ia n flu v ia l se rie s o c c u r d ire c tly o n y o u n g e r E lste ria n d e g la c ia tio n su ites. T h e y re p r e s e n t g ra v e lly o r s a n d y -g ra v e lly s e q u e n c e s d e p o s ite d by b ra id e d riv e rs . P o s s ib le H o lste in ia n flu v ia l d e p o s its h a v e b e e n d o c u m e n te d fo r th e first tim e in th e D o b ro c in q u a rry . H o ls te in ia n a g e is in fe rre d fro m th e g e o lo g ic a l p o sitio n . N o p o lle n d a ta are a v a ila b le .

4. E lste ria n a n d H o lste in ia n d e p o sits h a v e b e e n te c to n i- c a lly u p lifte d on th e D o b ro c in -W łó k i g n e is s ic h o rs t a n d slig h ty d e fo rm e d . T h e u p lift is c a 30 - 4 0 m . A g e o f u p lift